1. Field of the Invention
The present invention relates to an interlock device for a high-voltage apparatus, and particularly relates to an interlock device that enables a high-voltage apparatus to be interrupted mechanically and electrically for maintenance and inspection.
2. Description of the Background Art
A hybrid vehicle and an electric vehicle are configured such that a breaker device and a high-voltage apparatus are placed in a space separated from a passenger compartment and a luggage compartment, and covered with a maintenance lid to be contained in an enclosed space. In performing maintenance and inspection on the high-voltage apparatus, sufficient safety measures are indispensable to ensure safety against the high voltage thereof. For example, there is provided a technique for providing an interlock switch in the high-voltage apparatus described below.
TOYOTA Technical Review (Publication No. 14136) discloses an interlock switch of a power control unit (PCU) having a simplified mounting structure and wiring. The interlock switch is formed of a PCU case, a waterproof grommet, a wire harness, an interlock electrode, a PCU cover, and a bolt.
For the interlock switch of the PCU disclosed in the above-described document, the interlock switch is formed of the interlock electrode, the PCU cover, and the PCU case. As such, the interlock switch has a simplified mounting structure and wiring, compared with a connector-type interlock switch attached to the PCU cover via a bracket, which results in the reduced cost thereof and the reduced number of assembling steps therefor.
As shown in FIG. 1, for example, an interlock switch 902 to be provided at a high-voltage apparatus is conventionally placed at a housing 906. Interlock switch 902 is kept turned on when an upper cover 900 is attached, while interlock switch 902 is turned off when upper cover 900 is removed. When interlock switch 902 is turned off, power supply to an inverter provided within housing 906 is interrupted. Therefore, when a worker aims to remove upper lid 900, power supply to the inverter is not interrupted until upper cover 900 is lifted up. In order that a worker can perform maintenance and inspection in a safer manner, the interlock is required to be activated earlier than the time when upper cover 900 is lifted up.
In the interlock switch disclosed in the above-described document, electrical conduction among the PCU cover, the PCU case, and the interlock electrode is also interrupted when the PCU cover is removed. Therefore, this interlock switch has a similar problem described above.
Furthermore, since interlock switch 902 is required to be provided within housing 906, it is necessary to route a signal line 908 into housing 906. As a result, the interlock switch disadvantageously has a complicated structure, which increases manufacturing cost.